n-dhcp4: avoid {net,linux}/if.h clashes on old distros

In particular, avoid including linux/netdevice.h from headers. This is
not a problem on newer distros, but required for CentOS 7.6.

Signed-off-by: Tom Gundersen <teg@jklm.no>
12 jobs for nettools in 49 minutes and 37 seconds (queued for 2 minutes and 57 seconds)
Status Job ID Name Coverage
  Test
failed #336797
allowed to fail
checkpatch

00:01:14

manual #336802
allowed to fail manual
t_centos:7.5.1804
failed #336803
t_centos:7.6.1810

00:06:27

failed #336806
t_debian:9

00:04:09

canceled #336808
t_debian:sid

00:17:21

manual #336807
allowed to fail manual
t_debian:testing
passed #336798
t_fedora:28

00:28:22

passed #336799
t_fedora:29

00:37:17

passed #336800
t_fedora:30

00:29:15

manual #336801
allowed to fail manual
t_fedora:rawhide
failed #336804
t_ubuntu:16.04

00:04:13

passed #336805
t_ubuntu:18.04

00:17:43

 
Name Stage Failure
failed
t_debian:9 Test
make[2]: *** Waiting for unfinished jobs....
Makefile:12066: recipe for target 'shared/n-dhcp4/src/shared_libndhcp4_la-n-dhcp4-socket.lo' failed
make[2]: Leaving directory '/builds/tomegun/NetworkManager/build'
make[1]: *** [all-recursive] Error 1
Makefile:16096: recipe for target 'all-recursive' failed
make[1]: Leaving directory '/builds/tomegun/NetworkManager/build'
Makefile:6925: recipe for target 'all' failed
make: *** [all] Error 2
ERROR: Job failed: exit code 1
failed
t_ubuntu:16.04 Test
make[2]: *** Waiting for unfinished jobs....
Makefile:12066: recipe for target 'shared/n-dhcp4/src/shared_libndhcp4_la-n-dhcp4-socket.lo' failed
make[2]: Leaving directory '/builds/tomegun/NetworkManager/build'
make[1]: *** [all-recursive] Error 1
Makefile:16096: recipe for target 'all-recursive' failed
make[1]: Leaving directory '/builds/tomegun/NetworkManager/build'
make: *** [all] Error 2
Makefile:6925: recipe for target 'all' failed
ERROR: Job failed: exit code 1
failed
t_centos:7.6.1810 Test
   struct  sockaddr ifru_hwaddr;
^
make[2]: *** [shared/n-dhcp4/src/shared_libndhcp4_la-n-dhcp4-socket.lo] Error 1
make[2]: *** Waiting for unfinished jobs....
make[2]: Leaving directory `/builds/tomegun/NetworkManager/build'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/builds/tomegun/NetworkManager/build'
make: *** [all] Error 2
ERROR: Job failed: exit code 1
failed
checkpatch Test

src/dhcp/nm-dhcp-nettools.c:1246: XXX marker are reserved for development while work-in-progress. Use TODO or FIXME comment instead?:
> /* XXX: select hostname/FQDN */

The patch does not validate.
Uploading artifacts...
checkpatch-out.txt: found 1 matching files
Uploading artifacts to coordinator... ok
id=336797 responseStatus=201 Created token=A98UJ7C8
ERROR: Job failed: exit code 1